Prosecution Insights
Last updated: July 17, 2026
Application No. 18/546,822

AIR-CLEANING FILTER HAVING DUST COLLECTING AND DEODORIZING FUNCTIONS AND PREPARATION METHOD THEREFOR

Final Rejection §103
Filed
Aug 17, 2023
Priority
Feb 26, 2021 — RE 10-2021-0026907 +1 more
Examiner
SPAMER, DONALD R
Art Unit
1799
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Coway Co., Ltd.
OA Round
2 (Final)
60%
Grant Probability
Moderate
3-4
OA Rounds
0m
Est. Remaining
91%
With Interview

Examiner Intelligence

Grants 60% of resolved cases
60%
Career Allowance Rate
337 granted / 564 resolved
-5.2% vs TC avg
Strong +32% interview lift
Without
With
+31.5%
Interview Lift
resolved cases with interview
Typical timeline
2y 9m
Avg Prosecution
35 currently pending
Career history
595
Total Applications
across all art units

Statute-Specific Performance

§101
0.6%
-39.4% vs TC avg
§103
90.4%
+50.4% vs TC avg
§102
1.2%
-38.8% vs TC avg
§112
5.9%
-34.1% vs TC avg
Black line = Tech Center average estimate • Based on career data from 564 resolved cases

Office Action

§103
Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Claim amendments filed 3/16/2026 are acknowledged. Claims 1-20 are pending. Response to Arguments Arguments filed 3/16/2026 have been considered. New claim limitations are addressed below. In response to any arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). Additionally, the prior art may use different motivations to arrive at the claimed invention than the applicant. Claim Rejections - 35 USC § 103 The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. Claims 1-10 and 12-20 are rejected under 35 U.S.C. 103 as being unpatentable over Ptak et al. (US 2010/0247404) in view of Minemura et al. (US 2003/0207635), Liu (CN 106861288) (English machine transaction), and Togashi et al. US 8,308,855). With regards to claim 1, Ptak et al. teaches an air purifying filter (abstract) which comprises a pleated filter medium (fig 9) wherein the filter medium comprises multiple layers (fig 1-8). The layers can include layers made of non-woven fabric (para [0022] and [0034]) that are physically or chemically laminated together (abstract and para [0007] and elsewhere). The filter media can have a dust collecting filter layer (upstream layer can be a particulate filter and can be electrostatically charged), a deodorizing filter layer (downstream layer can have different function including odor and VOC removal), and a functional filter layer (antimicrobial properties or photocatalyst like titanium dioxide (para [0035]; there can be multiple downstream layers (see at least fig 2, 4, 6, and 8). The deodorizing filter can include activated carbon particles or zeolite (para [0022], [0036]). Ptak et al. does not expressly teach a deodorizing layer and at least one gas adsorbent for the functional filter layer, but Ptak et al. does contemplate using other arrangements with more layers and different combinations to achieve the desired filtration (para [0032], [0033], [0042]). A person having ordinary skill in the art would have found it obvious to have duplicated the deodorizing filter layer to include both an active carbon layer and a zeolite layer in order to achieve the desired odor and VOC adsorption through multiple different adsorptions and more total adsorptive material. Ptak et al. does not teach a particle size of the activated carbon particles or the amount of the activated carbon as claimed. Minemura et al. teaches an absorptive gas filter layer using activated carbon. Minemura et al. teaches balancing particle size to achieve good absorption with minimized negative effects such as pressure loss across a range of 60 to 600 microns (para [0044]). A person having ordinary skill in the art would have found it obvious to have optimized the particle size of the activated carbon in order to achieve the desired absorption and flow (pressure loss) as taught by Minemura et al. As to the amount of adsorbing carbon dioxide, Togashi teaches binding adsorbent material to a nonwoven filter media (column 15, lines 33-58). The amount of adsorbent can be optimized for filter performance (clogging) and adsorption (amount of deodorizing and capturing) (column 16, lines 22-39). A person having ordinary skill in the art would have found it obvious to have optimized the amount of adsorptive activated carbon material in order to achieve the desired filter performance and adsorption removal of VOCs. Ptak is silent as to the grammage of the non woven fiber filters. It is thus necessary and therefore obvious to look to the prior art for known grammages for use in non woven air filter material. Liu et al. teaches using a non woven fiber filter layer that has a gram weight of 10-100 g/m2 (“The fiber filter layer mainly plays the role of supporting the activated carbon particle layer, and the base material includes at least one of non-woven fabric, PP, and fiber cotton. Its gram weight is 10-100g/m 2”). A person having ordinary skill in the art would have found it obvious to have used non woven fabric filters with a grammage in the taught range motivated by an expectation of successfully providing non woven filter layers for air filter media. Further a person having ordinary skill in the art would have found it obvious to have optimized the grammage in order to achieve the desired filtration properties. With regards to claim 2, Ptak et al. teaches that the filters can be non-woven fabrics that are melt blown, spun bonded, or thermal bonded (para [0034], [0007]). A person having ordinary skill in the art would have found it obvious to have used non woven fabrics that are melt blow, spun bound, or thermal bonded motivated by an expectation of successfully forming the filter media. Ptak is silent as to the grammage of the non woven fiber filters. It is thus necessary and therefore obvious to look to the prior art for known grammages for use in non woven air filter material. Liu et al. teaches using a non woven fiber filter layer that has a gram weight of 10-100 g/m2 (“The fiber filter layer mainly plays the role of supporting the activated carbon particle layer, and the base material includes at least one of non-woven fabric, PP, and fiber cotton. Its gram weight is 10-100g/m 2”). A person having ordinary skill in the art would have found it obvious to have used non woven fabric filters with a grammage in the taught range motivated by an expectation of successfully providing non woven filter layers for air filter media. Further a person having ordinary skill in the art would have found it obvious to have optimized the grammage in order to achieve the desired filtration properties. With regards to claim 3, the functional filter is capable of the intended use of removing at least one of ammonia, aldehydes, acetic acid, toluene, and terpenes (removes VOCs and includes zeolite like the claimed invention; para [0022], [0035]) and the gas adsorbent is zeolite (para [0022]). With regards to claim 4, the combination teaches a functional filter layer with an adsorbent but does not teach one of phosphoric acid or ethylene urea. Togashi teaches binding adsorbent material to a nonwoven filter media (column 15, lines 33-58). Togashi teaches that the adsorbent material can be ethylene urea for adsorbing aldehydes (column 14, lines 27-32). The amount of adsorbent can be optimized for filter performance (clogging) and adsorption (amount of deodorizing and capturing) (column 16, lines 22-39). A person having ordinary skill in the art would have found it obvious to have used a functional filter layer with ethylene urea in order to remove aldehydes as taught by Taguchi. A person having ordinary skill in the art would have found it obvious to have optimized the amount of ethylene urea in order to achieve the desired filter performance and aldehyde removal. With regards to claim 5, the combination above results in the deodorizing filter layer and the dust collecting filter layer are laminated adjacent to each other, and the functional filter layer is laminated on the deodorizing filter layer or the dust collecting filter layer. Additionally, Ptak is not limiting on the order of filter layers describing different layers as possible on the upstream or downstream side (see whole document). Ptak also emphasizes the benefits of flexible design to achieve the desired application goals (para [0033]). A person having ordinary skill in the art would have found it obvious to have ordered the filter media as desired in order to achieve the desired filter function and performance. With regards to claim 6, the filter media of Ptak is adopted into an air purifier (fig 10). As to the order of filter material layers, the modification above addresses the claimed order. With regards to claim 7, Ptak teaches that a filter layer can be a titanium dioxide catalyst (para [0022], [0035], [0039]). A person having ordinary skill in the art would have found it obvious to have added a fourth nonwoven fabric filter layer with a catalyst in order to provide the taught catalytic air treatment. In the instance the applicant thinks the metal oxide, titanium dioxide, falls outside the genus of metal catalysts, Liu et al. teaches that one or more of Pt, Pd, Au, Ru, Rh, Ag can be used as a formaldehyde removal catalyst alongside titanium dioxide catalysts (see whole document). A person having ordinary skill in the art would have found it obvious to have used a coating of one or more of Pt, Pd, Au, Ru, Rh, Ag powder as a catalyst on a catalyst filter layer in order to provide the desired removal of formaldehyde in the air. With regards to claim 8, Ptak is not limiting on the order of filter layers laminated together describing different layers as possible on the upstream or downstream side (see whole document). Ptak also emphasizes the benefits of flexible design to achieve the desired application goals (para [0033]). A person having ordinary skill in the art would have found it obvious to have ordered the filter media as desired in order to achieve the desired filter function and performance. With regards to claim 9, the filter as modified above in claim 1 results in all the same structure as the claimed filter. Thus it is taken that the taught filter would have the same removal performance as claimed (the same recited structure would logically have to perform the same). It is additionally presented that Togashi teaches that the removal and elimination of acetaldehyde, toluene, and ammonia (at least column 14, lines 21-26). A person having ordinary skill in the art would have found it obvious to have designed the filter in order to have the desired removal of these compounds known to be undesirable in the purified air. With regards to claim 10, Ptak et al. teaches an air purifying filter (abstract) which comprises a pleated filter medium (fig 9) wherein the filter medium comprises multiple layers (fig 1-8). The layers can include layers made of non-woven fabric (para [0022] and [0034]) that are physically or chemically laminated together (abstract and para [0007] and elsewhere). The filter media can have a dust collecting filter layer (upstream layer can be a particulate filter and can be electrostatically charged), a deodorizing filter layer (downstream layer can have different function including odor and VOC removal), and a functional filter layer (antimicrobial properties or photocatalyst like titanium dioxide (para [0035]; there can be multiple downstream layers (see at least fig 2, 4, 6, and 8). The deodorizing filter can include activated carbon particles or zeolite (para [0022], [0036]). Ptak et al. does not expressly teach a deodorizing layer and at least one gas adsorbent for the functional filter layer, but Ptak et al. does contemplate using other arrangements with more layers and different combinations to achieve the desired filtration (para [0032], [0033], [0042]). A person having ordinary skill in the art would have found it obvious to have duplicated the deodorizing filter layer to include both an active carbon layer and a zeolite layer in order to achieve the desired odor and VOC adsorption through multiple different adsorptions and more total adsorptive material. Ptak et al. does not teach a particle size of the activated carbon particles or the amount of the activated carbon as claimed. Minemura et al. teaches an absorptive gas filter layer using activated carbon. Minemura et al. teaches balancing particle size to achieve good absorption with minimized negative effects such as pressure loss across a range of 60 to 600 microns (para [0044]). A person having ordinary skill in the art would have found it obvious to have optimized the particle size of the activated carbon in order to achieve the desired absorption and flow (pressure loss) as taught by Minemura et al. As to the amount of adsorbing carbon dioxide, Togashi teaches binding adsorbent material to a nonwoven filter media (column 15, lines 33-58). The amount of adsorbent can be optimized for filter performance (clogging) and adsorption (amount of deodorizing and capturing) (column 16, lines 22-39). A person having ordinary skill in the art would have found it obvious to have optimized the amount of adsorptive activated carbon material in order to achieve the desired filter performance and adsorption removal of VOCs. Ptak et al. teaches that the filters can be non-woven fabrics that are melt blown, spun bonded, or thermal bonded (para [0034], [0007]). A person having ordinary skill in the art would have found it obvious to have used no woven fabrics that are melt blow, spun bound, or thermal bonded motivated by an expectation of successfully forming the filter media. Ptak is silent as to the grammage of the nonwoven fiber filters. It is thus necessary and therefore obvious to look to the prior art for known grammages for use in nonwoven air filter material. Liu et al. teaches using a nonwoven fiber filter layer that has a gram weight of 10-100 g/m2 (“The fiber filter layer mainly plays the role of supporting the activated carbon particle layer, and the base material includes at least one of non-woven fabric, PP, and fiber cotton. Its gram weight is 10-100g/m 2”). A person having ordinary skill in the art would have found it obvious to have used nonwoven fabric filters with a grammage in the taught range motivated by an expectation of successfully providing nonwoven filter layers for air filter media. Further a person having ordinary skill in the art would have found it obvious to have optimized the grammage in order to achieve the desired filtration properties. Ptak is silent as to the binder. Togashi teaches making an air purifying filter using an adsorbent material adhered to a nonwoven fabric sheet. Togashi teaches doing so with a suitable binder in an amount of 5-30% by mass of the adsorbent being adhered (column 15, lines 33-58). A person having ordinary skill in the art would have found it obvious to have used a binder in an amount within the taught range motivated by an expectation of successfully adhering the activated carbon to the non-woven fabric filter media. With regards to claim 12, the combination results in the air purifying filter being used in an air purifier (fig 10 of Ptak). With regards to claim 13, Ptak et al. teaches an air purifying filter (abstract) which comprises a pleated filter medium (fig 9) wherein the filter medium comprises multiple layers (fig 1-8). The layers can include layers made of non-woven fabric (para [0022] and [0034]) that are physically or chemically laminated together (abstract and para [0007] and elsewhere). The filter media can have a dust collecting filter layer (upstream layer can be a particulate filter and can be electrostatically charged), a deodorizing filter layer (downstream layer can have different function including odor and VOC removal), and a functional filter layer (antimicrobial properties or photocatalyst like titanium dioxide (para [0035]; there can be multiple downstream layers (see at least fig 2, 4, 6, and 8). The deodorizing filter can include activated carbon particles or zeolite (para [0022], [0036]). Ptak et al. does not expressly teach a deodorizing layer and at least one gas adsorbent for the functional filter layer, but Ptak et al. does contemplate using other arrangements with more layers and different combinations to achieve the desired filtration (para [0032], [0033], [0042]). A person having ordinary skill in the art would have found it obvious to have duplicated the deodorizing filter layer to include both an active carbon layer and a zeolite layer in order to achieve the desired odor and VOC adsorption through multiple different adsorptions and more total adsorptive material. Ptak et al. does not teach a particle size of the activated carbon particles or the amount of the activated carbon as claimed. Minemura et al. teaches an absorptive gas filter layer using activated carbon. Minemura et al. teaches balancing particle size to achieve good absorption with minimized negative effects such as pressure loss across a range of 60 to 600 microns (para [0044]). A person having ordinary skill in the art would have found it obvious to have optimized the particle size of the activated carbon in order to achieve the desired absorption and flow (pressure loss) as taught by Minemura et al. As to the amount of adsorbing carbon dioxide, Togashi teaches binding adsorbent material to a nonwoven filter media (column 15, lines 33-58). The amount of adsorbent can be optimized for filter performance (clogging) and adsorption (amount of deodorizing and capturing) (column 16, lines 22-39). A person having ordinary skill in the art would have found it obvious to have optimized the amount of adsorptive activated carbon material in order to achieve the desired filter performance and adsorption removal of VOCs. Ptak et al. teaches that the filters can be non-woven fabrics that are melt blown, spun bonded, or thermal bonded (para [0034], [0007]). A person having ordinary skill in the art would have found it obvious to have used nonwoven fabrics that are melt blow, spun bound, or thermal bonded motivated by an expectation of successfully forming the filter media. Ptak is silent as to the grammage of the nonwoven fiber filters. It is thus necessary and therefore obvious to look to the prior art for known grammages for use in nonwoven air filter material. Liu et al. teaches using a nonwoven fiber filter layer that has a gram weight of 10-100 g/m2 (“The fiber filter layer mainly plays the role of supporting the activated carbon particle layer, and the base material includes at least one of non-woven fabric, PP, and fiber cotton. Its gram weight is 10-100g/m 2”). A person having ordinary skill in the art would have found it obvious to have used nonwoven fabric filters with a grammage in the taught range motivated by an expectation of successfully providing nonwoven filter layers for air filter media. Further a person having ordinary skill in the art would have found it obvious to have optimized the grammage in order to achieve the desired filtration properties. Ptak is silent as to the binder. Togashi teaches making an air purifying filter using an adsorbent material adhered to a nonwoven fabric sheet. Togashi teaches doing so with a suitable binder in an amount of 5-30% by mass of the adsorbent being adhered (column 15, lines 33-58). A person having ordinary skill in the art would have found it obvious to have used a binder in an amount within the taught range motivated by an expectation of successfully adhering the activated carbon to the non-woven fabric filter media. Ptak teaches that the filter layers are subsequently pleated (abstract). The combination results in the claimed preparing, binding, laminating, and pleating steps. With regards to claims 14-20, Ptak teaches that the filters are placed in an air purifier (fig 10). Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over Ptak et al. (US 2010/0247404) in view of Minemura et al. (US 2003/0207635), Liu (CN 106861288) (English machine transaction), and Togashi et al. US 8,308,855) as applied to claim 11 above and further in view of Filipovic (US 2021/0207843). With regards to cvlaim 11, the combination is silent as to the pressure differential of the air purifying filter. Filipovic teaches that a pressure differential across a filter is an important parameter and that higher pressure difference needs the fan to operate at a higher rate to achieve the same air flow (para [0023]). The differential pressure can be affected by the pore size (MERV rating, what size particles can be trapped) and dust clogging (para [0053]). A person having ordinary skill in the art would have found it obvious to have optimized the differential pressure of the filter in order to achieve the desired air flow while filtering the desired particles from the airflow. Conclusion Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a). A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action. Any inquiry concerning this communication or earlier communications from the examiner should be directed to DONALD R SPAMER whose telephone number is (571)272-3197. The examiner can normally be reached Monday to Friday from 9-5. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Michael Marcheschi can be reached at (571)272-1374. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /DONALD R SPAMER/Primary Examiner, Art Unit 1799
Read full office action

Prosecution Timeline

Aug 17, 2023
Application Filed
Dec 15, 2025
Non-Final Rejection mailed — §103
Mar 16, 2026
Response Filed
Jun 01, 2026
Final Rejection mailed — §103 (current)

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Prosecution Projections

3-4
Expected OA Rounds
60%
Grant Probability
91%
With Interview (+31.5%)
2y 9m (~0m remaining)
Median Time to Grant
Moderate
PTA Risk
Based on 564 resolved cases by this examiner. Grant probability derived from career allowance rate.

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